For example, a high speed interface such as a USB or an HDMI uses a “differential transmission system” for transmitting signals having different phases by 180° through a pair of signal lines. Since radiation noises or external noises are offset in a balanced line, the differential transmission system is hardly influenced by these noises. However, in actuality, noise current in a common mode based on asymmetry of a signal line for a high speed interface is generated particularly in the signal line. For this reason, a common mode choke coil is used in order to control the common mode noise.
Usually, the common mode choke coil is configured as a small-sized laminated chip component including two coils (a primary coil and a secondary coil) wound in the same direction as is disclosed in FIG. 1 of Patent Literature 1, FIG. 2 of Patent Literature 2 and the like. The primary coil and the secondary coil are arranged symmetrically in a lamination direction in a laminated element body.
FIG. 20 is a sectional view showing the common mode choke coil described in the Patent Literature 1. The common mode choke coil has a structure including two coils (laminated coils) 2 and 3 wound coaxially and arranged separately from each other in an axial direction in a laminated element 1, and starting ends and terminating ends of the respective coils 2 and 3 are led to end faces at both sides of the laminated element 1 and are connected to predetermined external electrodes.